Just to let you know - we took him to the vets this morning and they've given him an injection 'to settle his stomach' which'll last for 24hrs and some sensitive tinned dog food, which I'm meant to feed him a spoon of every half hour until his apetite is back and then mix in with his normal food gradually.
That was at 10.30am. Since then, the spoon was very unsuccessful so tried a little syringe. I put in about a 5p coins size of food into his mouth about once an hour since, and each time about 15mins later he'd throw back up this grey water. I phoned the vets back again about 5pm who said to give up for today, and try again tomorrow morning, and if no better to take him back in for bloods and an xray

The only good thing is, last night my OH came up with the idea that Dylan only really does poo when we take him for a walk, so we put him on the lead about 11pm last night and walked to the end of our road and he poo'd! Just a little, but perfectly formed

He's peed several times too now as he's not going out to eat grass any more (which is alittle more worrying that he's being sick without grass and still not eating).
Fingers crossed for a hungry dog tomorrow!